Have you seen the CDP thread in the tools forum? This problem seems to come up every other page, and can be dependent on different things…though the latest CDP release should alleviate the problem, apparently on your end it doesn’t.
What OS/system are you using, linux / mac / pc? What process are you trying, does for example ‘Distort interpolate’ work, but the fft processes like ‘blur average’ don’t? See the CDP thread last thread pages for possible solutions; https://forum.renoise.com/t/new-tool-3-0-cdp-lua-tool/41466